Exemplary embodiments relate to memory devices, and more particularly to a semiconductor memory device, a memory system including the same and a method of operating a semiconductor memory device.
Along with rapid developments in capacities and speeds of semiconductor memory devices widely used in electronic devices, power consumption of semiconductor memory devices has been increasing. Particularly, in case of portable electronic devices, it is very important to reduce power consumption of semiconductor memory devices in portable electronic devices.
For example, a dynamic random access memory (DRAM) is a volatile semiconductor memory device which stores data by using charges stored in a capacitor. Since charges stored in a capacitor may be leaked in various ways as time passes, a DRAM has a finite data retention characteristic. For solving finite data retention, it is typically necessary for a DRAM to refresh periodically to charge/discharge a capacitor according to data stored in the DRAM.
However, the power is more consumed for performing a refresh operation in the DRAM as increasing the memory density. Thus, decreasing power consumption for high-density memory devices is important.